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authorLinus Torvalds <torvalds@linux-foundation.org>2008-10-10 13:10:51 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-10-10 13:10:51 -0700
commitb922df7383749a1c0b7ea64c50fa839263d3816b (patch)
treedd72306ac173753649eb049d6d2734f4e2b95ff6 /include/linux/compiler.h
parentc54dcd8ec9f05c8951d1e622e90904aef95379f9 (diff)
parentcdbb92b31d3c465aa96bd09f2d42c39b87b32bee (diff)
Merge branch 'rcu-v28-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'rcu-v28-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (21 commits) rcu: RCU-based detection of stalled CPUs for Classic RCU, fix rcu: RCU-based detection of stalled CPUs for Classic RCU rcu: add rcu_read_lock_sched() / rcu_read_unlock_sched() rcu: fix sparse shadowed variable warning doc/RCU: fix pseudocode in rcuref.txt rcuclassic: fix compiler warning rcu: use irq-safe locks rcuclassic: fix compilation NG rcu: fix locking cleanup fallout rcu: remove redundant ACCESS_ONCE definition from rcupreempt.c rcu: fix classic RCU locking cleanup lockdep problem rcu: trace fix possible mem-leak rcu: just rename call_rcu_bh instead of making it a macro rcu: remove list_for_each_rcu() rcu: fixes to include/linux/rcupreempt.h rcu: classic RCU locking and memory-barrier cleanups rcu: prevent console flood when one CPU sees another AWOL via RCU rcu, debug: detect stalled grace periods, cleanups rcu, debug: detect stalled grace periods rcu classic: new algorithm for callbacks-processing(v2) ...
Diffstat (limited to 'include/linux/compiler.h')
-rw-r--r--include/linux/compiler.h4
1 files changed, 3 insertions, 1 deletions
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index c8bd2daf95e..8322141ee48 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -190,7 +190,9 @@ extern void __chk_io_ptr(const volatile void __iomem *);
* ACCESS_ONCE() in different C statements.
*
* This macro does absolutely -nothing- to prevent the CPU from reordering,
- * merging, or refetching absolutely anything at any time.
+ * merging, or refetching absolutely anything at any time. Its main intended
+ * use is to mediate communication between process-level code and irq/NMI
+ * handlers, all running on the same CPU.
*/
#define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))